Aqueous dispersions for antioxidants

ABSTRACT

The present invention relates to aqueous dispersions for solid phenolic antioxidants, wherein the antioxidants are dispersed in the aqueous phase with polyvinyl alcohol as dispersing agent. The invention also relates to a process, which comprises stabilising a polymer material against oxidative, thermal or light-induced degradation by adding to the polymer the aqueous dispersion.

The present invention relates to aqueous dispersions for solid phenolicantioxidants, a process for preparing the aqueous dispersions, thefurther processing of the aqueous dispersion and a polymer compositioncomprising the dispersed components of the aqueous dispersion. Theinvention particularly relates to storage-stable, non-sedimentingemulsions comprising phenolic antioxidants, for example for use forstabilising emulsion-polymerised polymers and copolymers againstatmospheric oxidative reactions.

Solid additives, such as certain commercial phenolic antioxidants fromthe Irganox® (trade mark of Ciba Specialty Chemicals) series, e.g.IRGANOX 1076:Octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate, are used fora great variety of technical applications, e.g. for the stabilisation ofpolymers against oxidative, thermal or light induced degradation. Asmall particle size is preferred to assure the efficiency of theadditive used. The ideal particle size should be mainly in the rangefrom 0.1 to 10.0μ. Any particle size smaller than 5.0μ is particularlypreferred.

Wet grinding, as opposed to grinding of dry particles, is a standardmethod for obtaining particles of this small size. This method combinesthe advantages of a reduction to small particles with the preparation ofa dispersion comprising the particles in an inert liquid. Suchdispersions are preferably prepared from solids by grinding withindeionised water as the dispersant phase and require the presence and/orsubsequent addition of various additives, such as surfactants,thickeners, and fungicides, to ensure the mechanical and chemicalstabilisation of the dispersion. The solids are prepared by work-upmethods, such as crystallisation, filtration, drying or grinding, in asequential step subsequent to their synthesis. The present inventionintends to replace the wet grinding step with a more convenient andfeasible step for reducing the particle size.

It has surprisingly been found that converting phenolic antioxidants toan aqueous dispersion, particularly to an emulsion, reduces the particlesize of solid phenolic antioxidants even further to the size of smalldroplets. It has not been known before that a melt prepared from solidmaterial of phenolic antioxidants of the formula (I) is dispersible asan emulsion in an aqueous phase wherein the non-ionic surfactantpolyvinyl alcohol is dispersed. The preparation of a molten phase andits subsequent dispersion to give an emulsion is clearly more beneficialthan the standard method of isolating a solid, e.g. by crystallisation,and its subsequent wet grinding.

The present invention relates to an aqueous dispersion comprising

-   -   a) A compound of the formula:    -    Wherein    -    One of R₁ and R₂ independently of one another represents        hydrogen or C₁-C₄alkyl and the other one represents C₃-C₄alkyl;    -    x represents zero (direct bond) or a numeral from one to three;        and    -    R₃ represents C₈-C₂₂alkyl; or groups of the partial formulae    -    Wherein    -    One of R₁′ and R₂′ independently of one another represents        hydrogen or C₁-C₄alkyl and the other one represents C₃-C₄alkyl;    -    x represents zero (direct bond) or a numeral from one to three;        and    -    y represents a numeral from two to six;    -   b) Polyvinyl alcohol having a degree of polymerisation of about        500-2 500 and a degree of hydrolysis of about 70.0-99.9%; and,        optionally, further additives; and    -   c) Water.

The general terms used in the description of the instant invention,unless defined otherwise, are defined as follows:

The term aqueous dispersion comprises any mixture of two phases whereindispersed particles are distributed homogeneously in a dispersant phase(dispergens), which in the instant case is water.

The term aqueous dispersion is defined within the limits of so-calledsolid/liquid or liquid/liquid disperse systems, e.g. emulsion,dispersion, as opposed to other types of dispersions, such as solid/gas,e.g. fumes, or gas/liquid, e.g. foams, dispersions. Solid/liquiddispersions that apply here consist of a two-phase system containinginsoluble solid particles or solid particles of low solubility within aliquid. Liquid/liquid dispersions are commonly defined as emulsions andconsist of two separate phases of different polarity. In the instantcase a non-polar phase is dispersed in the polar phase, which is water.

The term dispersed particles comprises solid and, in particular, liquidparticles, in the instant case the compound of the formula (I), to bedistributed homogeneously within a liquid phase, e.g. water. Homogeneousdistribution means that the concentration of the solid or liquidparticles within the liquid dispersion agent is identical orapproximately identical in any volume fraction of that liquid phase(even distribution of liquid or solid particles).

Component a)

In a compound of the formula (I) R₁ and R₂ defined as C₁-C₄alkylcomprise the unbranched and branched (where possible) groups methyl,ethyl, n-propyl, isopropyl, n-butyl, isobutyl and tert-butyl.

R₁ and R₂ defined as C₃-C₄alkyl comprises the unbranched and preferablybranched groups, e.g. isopropyl, isobutyl or tert-butyl.

In a preferred embodiment of the invention one of R₁ and R₂ representshydrogen or C₁-C₄alkyl, particularly methyl or tert-butyl, and the otherone represents C₃-C₄alkyl, particularly tert-butyl.

The numeral x represents zero or a numeral from one to three.

In the event that x is zero, the direct bond is defined.

In the event that x is one, the group C_(x)H_(2x), represents methylene.

In the event that x represents the numeral two, the group—[C_(x)H_(2x)]— represents 1,1- or preferably 1,2-ethylene.

In the event that x represents the numeral three, the group—[C_(x)H_(2x)]— represents 1,1-, 1,2- or preferably 1,3-propylene.

R₃ defined as C₈-C₂₂alkyl represents, for example n-octyl, 2-ethylhexyl,1,1,3,3-tetramethylbutyl, 1-methylheptyl, n-nonyl or1,1,3-trimethylhexyl or C₁₀-C₂₂alkyl, particularly straight chainC₁₀-C₂₂alkyl, e.g. n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl orn-octadecyl or higher homologues thereof.

A particularly preferred compound, wherein R₁ and R₂ representtert-butyl, R₃ represents C₁₀-C₂₂alkyl, particularly n-octadecyl, and xis the numeral two, is IRGANOX 1076:n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

In a compound (I) wherein R₃ represents groups of the partial formulae(A) and (B), R₁′ and R₂′ have the same meanings as defined above withregard to R₁ and R₂. Preferably one of R₁′ and R₂′ represents methyl ortert-butyl and the other one represents C₃-C₉alkyl, particularlytert-butyl.

In a compound (I) wherein R₃ represents the group of the partial formula(A), y represents a numeral from two to six, preferably three.

A particularly preferred compound (I), wherein one of R₁ and R₂represents methyl and the other one represents tert-butyl, x representstwo, R₃ represents a group of the partial formula A, wherein R₁′ and R₂′are as defined as R₁ and R₂, x represents two and y represents three, isIRGANOX 245:ethylene-bis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)-propionate].

A particularly preferred compound (I), wherein R₁ and R, representstert-butyl, x represents three and R₃ represents a group of the partialformula B, wherein R₁′ and R₂′ are as defined as R₁ and R₂ and xrepresents two, is IRGANOX 1010:tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate].

Component b)

Suitable polyvinyl alcohols are obtainable by hydrolysis of polyvinylacetate and have a mean molar mass of approximately 15 000 to 250 000,which corresponds to a degree of polymerisation of about 500-2 500.Suitable polyvinyl alcohols have a degree of hydrolysis of about70.0-99.9 mol % and are characterised by their viscosity (of a 4%aqueous solution) according to DIN 53 015 from 2.5 to 60.0 [mPa.s]. Theester value according to DIN 53 401 decreases from 220 to 8.0 [mg KOH/g]and the residual acetyl content from 17.0 to 0.2% by weight with anincreasing degree of hydrolysis.

Suitable polyvinyl alcohols are the commercial products obtainable underthe trademark Mowiol® (Clariant GmbH, D-65926 Frankfurt). Specialreference is made to the products 3- and 15-96; 3-, 4-, 6-, 10-, 20- and56-98; or 15- and 28-99 (fully hydrolysed grades).

Particularly preferred are the commercial products 15-79; 3-83; 4-, 5-,8-, 18-, 23-, 26-, 40-, 47- and 56-88; 30-92 (partially hydrolysedgrades).

Component c)

Water is present in the dispersion as the remainder to make 100.0% byweight. The addition of purified, e.g. deionised or distilled, water ispreferred.

The aqueous dispersion of the invention may comprise additionaladditives suitable for use in polymers, preferably additives customarilyused for improving the chemical and physical properties of polymerscontaining these additives. The auxiliaries can be present in thedispersion in varying proportions, for example, in amounts of up to40.0% by weight, preferably from 0.05% to 40.0% by weight, morepreferably from 0.05% to 25.0% by weight, with particular preferencefrom 0.05% to 10.0% by weight based on the total weight of thecomposition. Suitable groups of additional additives are listed up hereby way of example: antioxidants selected from the group consisting ofalkylated monophenols, alkylthiomethylphenols, hydroquinones andalkylated hydroquinones, tocopherols, hydroxylated thiodiphenyl ethers,alkylidene-bis-phenols, O-, N- and S-benzyl compounds, hydroxybenzylatedmalonates, aromatic hydroxybenzyl compounds, triazine compounds,benzylphosphonates, acylaminophenols, esters and amides ofβ-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid,β-(3,5-di-t-butyl-4-hydroxy-3-methylphenyl)propionic acid, orβ-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid, ascorbic acid,aminic antioxidants, light stabilisers, phosphites, phosphines,phosponites, hydroxylamines, nitrones, thiosynergists, peroxidescavengers, polyamide stabilisers, basic co-stabilisers, nucleatingagents, fillers and reinforcing agents, plasticisers, lubricants,emulsifiers, pigments, rheological additives, levelling assistants,optical brighteners, flame proofing agents, antistatic agents, blowingagents, benzofuranones and indolinones.

Suitable additives optionally present in the aqueous dispersionaccording to the present invention may be selected from the followingnon-exhaustive list of specific additives:

1. Antioxidants

-   -   1.1. Alkylated monophenols, for example        2,6-di-t-butyl-4-methylphenol, 2-butyl-4,6-dimethylphenol,        2,6-di-t-butyl-4-ethylphenol, 2,6-di-t-butyl-4-n-butylphenol,        2,6-di-t-butyl-4-isobutylphenol,        2,6-dicyclopentyl-4-methylphenol,        2-(l-methylcyclohexyl)-4,6-dimethylphenol        2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol,        2,6-di-t-butyl-4-methoxymethylphenol, linear or side        chain-branched nonylphenols; such as 2,6-dinonyl-4-methylphenol,        2,4-dimethyl-6-(1-methylundec-1′-yl)phenol,        2,4-dimethyl-6-(1′-methylheptadec-1′-yl)phenol,        2,4-dimethyl-6-(1′-methyltridec-1′-yl)phenol and mixtures        thereof.    -   1.2. Alkylthiomethylphenols, for example        2,4-dioctylthiomethyl-6-t-butylphenol,        2,4-dioctylthiomethyl-6-methylphenol,        2,4-dioctylthiomethyl-6-ethylphenol,        2,6-didodecylthiomethyl-4-nonylphenol.    -   1.3 Hydroquinones and alkylated hydroquinones, for example        2,6-di-t-butyl-4-methoxyphenol, 2,5-di-t-butylhydroquinone,        2,5-di-t-amylhydroquinone, 2,6-diphenyl-4-octadecyloxyphenol,        2,6-di-t-butylhydroquinone, 2,5-di-t-butyl-4-hydroxyanisole,        3,5-di-t-butyl-4-hydroxyanisole, 3,5-di-t-butyl-4-hydroxyphenyl        stearate, bis(3,5-di-t-butyl-4-hydroxyphenyl)adipate.    -   1.4. Tocopherols, for example α-, β-, γ- or δ-tocopherols and        mixtures thereof (vitamin E).    -   1.5. Hydroxylated thiodiphenyl ethers, for example        2,2′-thio-bis(6-t-butyl-4-methylphenol),        2,2′-thio-bis(4-octylphenol),        4,4′-thio-bis(6-t-butyl-3-methylphenol),        4,4′-thio-bis(6-t-butyl-2-methylphenol),        4,4′-thio-bis(3,6-di-sec-amylphenol),        4,4′-bis(2,6-dimethyl-4-hydroxyphenyl) disulphide.    -   1.6. Alkylidene-bis-phenols, for example        2,2′-methylene-bis(6-t-butyl-4-methylphenol),        2,2′-methylene-bis(6-t-butyl-4-ethylphenol),        2,2′-methylene-bis[4-methyl-6-(l-methylcyclohexyl)phenol],        2,2′-methylene-bis(4-methyl-6-cyclohexylphenol),        2,2′-methylene-bis(6-nonyl-4-methylphenol),        2,2′-methylene-bis(4,6-di-t-butylphenol),        2,2′-ethylidene-bis(4,6-di-t-butylphenol),        2,2′-ethylidene-bis(6-t-butyl-4-isobutylphenol),        2,2′-methylene-bis[6-(α-methylbenzyl)-4-nonylphenol],        2,2′-methylene-bis[6-(α,α-dimethylbenzyl)-4-nonylphenol],        4,4′-methylene-bis(2,6-di-t-butylphenol),        4,4′-methylene-bis(6-t-butyl-2-methylphenol),        1,1-bis(5-t-butyl-4-hydroxy-2-methylphenyl)butane,        2,6-bis(3-t-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,        1,1,3-tris(5-t-butyl-4-hydroxy-2-methylphenyl)butane,        1,1-bis(5-t-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobutane,        ethylene glycol        bis[3,3-bis(3′-t-butyl-4′-hydroxyphenyl)butyrate],        bis(3-t-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene,        bis[2-(3′-t-butyl-2′-hydroxy-5′-methylbenzyl)-6-t-butyl-4-methylphenyl]terephthalate,        1,1-bis(3,5-dimethyl-2-hydroxyphenyl)butane,        2,2-bis(3,5-di-t-butyl-4-hydroxyphenyl)propane,        2,2-bis(5-t-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecylmercaptobutane,        1,1,5,5-tetra-(5-t-butyl-4-hydroxy-2-methylphenyl)pentane.    -   1.7. O-, N- and S-benzyl compounds for example,        3,5,3′,5′-tetra-t-butyl-4,4′-dihydroxydibenzyl ether, octadecyl        4-hydroxy-3,5-dimethylbenzylmercaptoacetate, tridecyl        4-hydroxy-3,5-di-t-butylbenzylmercaptoacetate,        tris(3,5-di-t-butyl-4-hydroxybenzyl)-amine,        bis(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate,        bis(3,5-di-t-butyl-4-hydroxybenzyl) sulphide, isooctyl        3,5-di-t-butyl-4-hydroxybenzylmercaptoacetate.    -   1.8. Hydroxybenzylated malonates, for example dioctadecyl        2,2-bis(3,5-di-t-butyl-2-hydroxybenzyl)malonate, dioctadecyl        2-(3-t-butyl-4-hydroxy-5-methylbenzyl)malonate, didodecyl        mercaptoethyl-2,2-bis(3,5-di-t-butyl-4-hydroxybenzyl)malonate,        di-[4-(1,1,3,3-tetramethylbutyl)phenyl]-2,2-bis(3,5-di-t-butyl-4-hydroxybenzyl)malonate.    -   1.9. Aromatic hydroxybenzyl compounds, for example        1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,        1,4-bis(3,5-di-t-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethylbenzene,        2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)phenol.    -   1.0. Triazine compounds, for example        2,4-bisoctylmercapto-6-(3,5-di-t-butyl-4-hydroxyanilino)-1,3,5-triazine,        2-octylmercapto-4,6-bis(3,5-di-t-butyl-4-hydroxyanilino)-1,3,5-triazine,        2-octylmercapto-4,6-bis(3,5-di-t-butyl-4-hydroxyphenoxy)-1,3,5-triazine,        2,4,6-tris(3,5-di-t-butyl-4-hydroxyphenoxy)-1,2,3-triazine,        1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate,        1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate,        2,4,6-tris(3,5-di-t-butyl-4-hydroxyphenylethyl)-1,3,5-triazine,        1,3,5-tris(3,5-di-t-butyl-4-hydroxyphenylpropionyl)hexahydro-1,3,5-triazine,        1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanurate.    -   1.11. Benzylphosphonates, for example dimethyl        2,5-di-t-butyl-4-hydroxybenzyl-phosphonate, diethyl        3,5-di-t-butyl-4-hydroxybenzylphosphonate, dioctadecyl        3,5-di-t-butyl-4-hydroxybenzylphosphonate, dioctadecyl        5-t-butyl-4-hydroxy-3-methylbenzylphosphonate, the calcium salt        of the monoethyl ester of        3,5-di-t-butyl-4-hydroxybenzylphosphonic acid.    -   1.12. Acylaminophenols, for example 4-hydroxylauranilide,        4-hydroxystearanilide, octyl        N-(3,5-di-t-butyl-4-hydroxyphenyl)carbamate.    -   1.13. Esters of β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid        with mono- or polyhydric alcohols, e.g. with methanol, ethanol,        n-octanol, 1-octanol, octadecanol, 1,6-hexanediol,        1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl        glycol, thiodiethylene glycol, diethylene glycol, triethylene        glycol, pentaerythritol, tris(2-hydroxyethyl)isocyanurate,        N,N′-bis(2-hydroxyethyl)oxalamide, 3-thiaundecanol,        3-thiapentadecanol, trimethylhexanediol, trimethylolpropane,        4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.    -   1.14. Esters of β-(5-t-butyl-4-hydroxy-3-methylphenyl)propionic        acid with mono- or polyhydric alcohols, e.g. with methanol,        ethanol, n-octanol, i-octanol, octadecanol, 1,6-hexanediol,        1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl        glycol, thiodiethylene glycol, diethylene glycol, triethylene        glycol, pentaerythritol, tris(2-hydroxyethyl)isocyanurate,        N,N′-bis(2-hydroxyethyl)oxalamide, 3-thiaundecanol,        3-thiapentadecanol, trimethylhexanediol, trimethylolpropane,        4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.    -   1.15. Esters of β-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic        acid with mono- or polyhydric alcohols, e.g. with methanol,        ethanol, octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol,        ethylene glycol, 1,2-propanediol, neopentyl glycol,        thiodiethylene glycol, diethylene glycol, triethylene glycol,        pentaerythritol, tris(2-hydroxyethyl)isocyanurate,        N,N′-bis(2-hydroxyethyl)oxalamide, 3-thiaundecanol,        3-thiapentadecanol, trimethylhexanediol, trimethylolpropane,        4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.    -   1.16. Esters of 3,5-di-t-butyl-4-hydroxyphenylacetic acid with        mono- or polyhydric alcohols, e.g. with methanol, ethanol,        octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene        glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene        glycol, diethylene glycol, triethylene glycol, pentaerythritol,        tris(2-hydroxyethyl)isocyanurate,        N,N′-bis(2-hydroxyethyl)-oxalamide, 3-thiaundecanol,        3-thiapentadecanol, trimethylhexanediol, trimethylolpropane,        4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.    -   1.17. Amides of β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic        acid, e.g.        N,N′-bis(3,5-di-t-butyl-4-hydroxyphenylpropionyl)hexamethylenediamide,        N,N′-bis(3,5-di-t-butyl-4-hydroxyphenylpropionyl)trimethylenediamide,        N,N′-bis(3,5-di-t-butyl-4-hydroxyphenylpropionyl)hydrazide,        N,N′-bis[2-(3-[3,5-di-t-butyl-4-hydroxyphenyl]propionyloxy)ethyl]oxamide        (Naugard® XL-1 from Uniroyal).    -   1.18. Ascorbic acid (vitamin C).    -   1.19. Aminic antioxidants, for example        N,N′-diisopropyl-p-phenylenediamine,        N,N′-di-sec-butyl-p-phenylenediamine,        N,N′-bis(1,4-dimethyl-pentyl)-p-phenylenediamine,        N,N′-bis(1-ethyl-3-methyl-pentyl)-p-phenylenediamine,        N,N′-bis(1-methylheptyl)-p-phenylenediamine,        N,N′-dicyclohexyl-p-phenylenediamine,        N,N′-diphenyl-p-phenylenediamine,        N,N′-di-(2-naphthyl)-p-phenylenediamine,        N-isopropyl-N′-phenyl-p-phenylenediamine,        N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine,        N-(1-methylheptyl)-N′-phenyl-p-phenylenediamine,        N-cyclohexyl-N′-phenyl-p-phenylenediamine,        4-(p-toluenesulphonamido)-diphenylamine,        N,N′-dimethyl-N,N′-di-sec-butyl-p-phenylenediamine,        diphenylamine, N-allyldiphenylamine, 4-isopropoxydiphenylamine,        N-phenyl-1-naphthylamine, N-(4-t-octylphenyl)-1-naphthylamine,        N-phenyl-2-naphthylamine, octylated diphenylamine, for example        p,p′-di-t-octyldiphenylamine, 4-n-butylaminophenol,        4-butyrylaminophenol, 4-nonanoylaminophenol,        4-dodecanoylaminophenol, 4-octadecanoylaminophenol,        di-(4-methoxyphenyl)amine,        2,6-di-t-butyl-4-dimethylaminomethylphenol,        2,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane,        N,N,N′,N′-tetramethyl-4,4′-diamino-diphenylmethane,        1,2-di[(2-methylphenyl)amino]ethane, 1,2-diphenylaminopropane,        (o-tolyl)biguanide, di-[4-(1′,3′-dimethylbutyl)phenyl]amine,        t-octylated N-phenyl-1-naphthylamine, a mixture of mono- and        dialkylated t-butyl/t-octyldiphenylamines, a mixture of mono-        and dialkylated nonyldiphenylamines, a mixture of mono- and        dialkylated dodecyldiphenylamines, a mixture of mono- and        dialkylated isopropyl/isohexyl-diphenylamines, mixtures of mono-        and dialkylated t-butyldiphenylamines,        2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine, phenothiazine, a        mixture of mono- and dialkylated t-butyl/t-octyl-phenothiazines,        a mixture of mono- and dialkylated t-octyl-phenothiazines,        N-allylphenothiazine,        N,N,N′,N′-tetraphenyl-1,4-diaminobut-2-ene,        N,N-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylenediamine,        bis(2,2,6,6-tetramethylpiperidin-4-yl)sebacate,        2,2,6,6-tetramethylpiperidin-4-one and        2,2,6,6-tetramethylpiperidin-4-ol.    -   1.20. Polyphenolic antioxidants, for example derivates of        p-cresol and dicyclopentadiene for example ®WINGSTAY L        (Goodyear), CAS-Nb 68610-51-5.

2. UV-absorbers and Light Stabilisers

-   -   2.1. 2-(2′-Hydroxyphenyl)benzotriazoles, for example        2-(2′-hydroxy-5′-methylphenyl)benzotriazole,        2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)benzotriazole,        2-(5′-tert-butyl-2′-hydroxyphenyl)benzotriazole,        2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole,        2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)-5-chlorobenzotriazole,        2-(3′-tert-butyl-2′-hydroxy-5′-methylphenyl)-5-chlorobenzotriazole,        2-(3′-sec-butyl-5′-tert-butyl-2′-hydroxyphenyl)benzotriazole,        2-(2′-hydroxy-4′-octyloxyphenyl)benzotriazole,        2-(3′,5′-di-tert-amyl-2′-hydroxyphenyl)benzotriazole,        2-(3′,5′-bis(α,α-dimethylbenzyl)-2′-hydroxyphenyl)benzotriazole,        2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)-5-chlorobenzotriazole,        2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)-5-chlorobenzotriazole,        2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)-5-chlorobenzotriazole,        2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)benzotriazole,        2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)benzotriazole,        2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)benzotriazole,        2-(3′-dodecyl-2′-hydroxy-5′-methylphenyl)benzotriazole,        2-(3′-tert-butyl-2′-hydroxy-5′-(2-isooctyloxycarbonylethyl)phenylbenzotriazole,        2,2′-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-benzotriazole-2-ylphenol];        the transesterification product of        2-[3′-tert-butyl-5′-(2-methoxycarbonylethyl)-2′-hydroxyphenyl]-2H-benzotriazole        with polyethylene glycol 300; R—CH₂CH₂—COO—CH₂CH₂        ₂,    -    wherein R represents        3′-tert-butyl-4′-hydroxy-5′-2H-benzotriazol-2-ylphenyl,        2-[2′-hydroxy-3′-(α,α-dimethylbenzyl)-5′-(1,1,3,3-tetramethylbutyl)phenyl]benzotriazole;        2-[2′-hydroxy-3′-(1,1,3,3-tetramethylbutyl)-5′-(α,α-dimethylbenzyl)phenyl]benzotriazole.    -   2.2. 2-Hydroxybenzophenones, for example the 4-hydroxy,        4-methoxy, 4-octyloxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy,        4,2′,4′-trihydroxy and 2′-hydroxy-4,4′-dimethoxy derivatives.    -   2.3. Esters of substituted and unsubstituted benzoic acids, for        example 4-tert-butylphenyl salicylate, phenyl salicylate,        octylphenyl salicylate, dibenzoyl resorcinol,        bis(4-tert-butylbenzoyl)resorcinol, benzoyl resorcinol,        2,4-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate,        hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl        3,5-di-tert-butyl-4-hydroxybenzoate,        2-methyl-4,6-di-tert-butylphenyl        3,5-di-tert-butyl-4-hydroxybenzoate.    -   2.4 Acrylates, for example ethyl lα-cyano-β,β-diphenyl acrylate        or isooctyl αl-cyano-β,β-diphenyl acrylate, methyl        α-carbomethoxycinnamate, methyl        αl-cyano-βl-methyl-p-methoxycinnamate or butyl        α-cyano-β-methyl-p-methoxycinnamate, methyl        αl-carbomethoxy-p-methoxycinnamate and        N-(α-carbomethoxy-β-cyanovinyl)-2-methylindoline.    -   2.5 Nickel compounds, for example nickel complexes of        2,2′-thio-bis[4-(1,1,3,3-tetramethylbutyl)phenol], such as the        1:1- or 1:2-complex, with or without additional ligands, such as        n-butylamine, triethanolamine or N-cyclohexyldiethanolamine,        nickel dibutyldithiocarbamate, nickel salts of monoalkyl esters,        such as of the methyl or ethyl ester, of        4-hydroxy-3,5-di-t-butylbenzylphosphonic acid, nickel complexes        of ketoximes, e.g. of 2-hydroxy-4-methylphenyl undecyl ketoxime,        nickel complexes of 1-phenyl-4-lauroyl-5-hydroxypyrazole, with        or without additional ligands.    -   2.6 Sterically hindered amines, for example        bis(2,2,6,6-tetramethylpiperidin-4-yl)sebacate,        bis(2,2,6,6-tetramethylpiperidin-4-yl) succinate,        bis(1,2,2,6,6-pentamethylpiperidin-4-yl)sebacate,        bis(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl)sebacate,        bis(1,2,2,6,6-pentamethylpiperidyl)        n-butyl-3,5-di-t-butyl-4-hydroxybenzylmalonate, the condensate        of 1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidine and        succinic acid, the linear or cyclic condensates of        N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine        and 4-t-octylamino-2,6-dichloro-1,3,5-s-triazine,        tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate,        tetrakis(2,2,6,6-tetramethyl-4-piperidyl)        1,2,3,4-butanetetraoate,        1,1′-(1,2-ethanediyl)bis(3,3,5,5-tetramethylpiperazinone),        4-benzoyl-2,2,6,6-tetramethylpiperidine,        4-stearyloxy-2,2,6,6-tetramethylpiperidine,        bis(1,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-t-butylbenzyl)malonate,        3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione,        bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)sebacate,        bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)succinate, the        linear or cyclic condensates of        N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine        and 4-morpholino-2,6-dichloro-1,3,5-triazine, the condensate of        2-chloro-4,6-di(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazine        and 1,2-bis(3-aminopropylamino)ethane, the condensate of        2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazine        and 1,2-bis(3-aminopropylamino)ethane,        8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione,        3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl)pyrrolidine-2,5-dione,        3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)pyrrolidine-2,5-dione,        a mixture of 4-hexadecyloxy- and        4-stearyloxy-2,2,6,6-tetramethylpiperidine, the condensate of        N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylenediamine        and 4-cyclohexylamino-2,6-dichloro-1,3,5-triazine, the        condensate of 1,2-bis(3-aminopropylamino)ethane and        2,4,6-trichloro-1,3,5-triazine and also        4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No.        [136504-96-6]);        N-(2,2,6,6-tetramethyl-4-piperidyl)-n-dodecylsuccinimide,        N-(1,2,2,6,6-pentamethyl-4-piperidyl)-n-dodecylsuccinimide,        2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxospiro[4.5]decane,        the reaction product of        7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro[4.5]decane        and epichlorohydrine,        1,1-bis(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyl)-2-(4-methoxyphenyl)ether,        N,N′-bis-formyl-N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylenediamine,        the diester of 4-methoxymethylenemalonic acid with        1,2,2,6,6-pentamethyl-4-hydroxypiperidine,        poly[methylpropyl-3-oxy-4-(2,2,6,6-tetramethyl-4-piperidyl)]siloxane,        the reaction product of maleic anhydride-α-olefin copolymer and        2,2,6,6-tetramethyl-4-aminopiperidine or        1,2,2,6,6-pentamethyl-4-aminopiperidine.    -   2.7 Oxalamides, for example 4,4′-dioctyloxyoxanilide,        2,2′-diethoxy-oxanilide,        2,2′-dioctyloxy-5,5′-di-t-butyloxanilide,        2,2′-didodecyloxy-5,5′-di-t-butyloxanilide,        2-ethoxy-2′-ethyloxanilide,        N,N′-bis(3-dimethylaminopropyl)oxalamide,        2-ethoxy-5-t-butyl-2′-ethyloxanilide and its mixture with        2-ethoxy-2′-ethyl-5,4′-di-t-butyloxanilide and mixtures of o-        and p-methoxy- and of o- and p-ethoxy-disubstituted oxanilides.    -   2.8 2-(2-Hydroxyphenyl)-1,3,5-triazines, for example        2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine,        2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,        2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,        2,4-bis(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine,        2-(2-hydroxy-4-octyloxyphenyl)-4,6bis(4-methylphenyl)-1,3,5-triazine,        2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,        2-(2-hydroxy-4-tridecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,        2-[2-hydroxy-4-(2-hydroxy-3-butyloxypropyloxy)phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,        2-[2-hydroxy-4-(2-hydroxy-3-octyloxypropyloxy)-phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,        2-[4-(dodecyloxy/tridecyloxy-2-hydroxypropoxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,        2-[2-hydroxy-4-(2-hydroxy-3-dodecyloxy-propoxy)phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,        2-(2-hydroxy-4-hexyloxy)phenyl-4,6-diphenyl-1,3,5-triazine,        2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine,        2,4,6-tris[2-hydroxy-4-(3-butoxy-2-hydroxy-propoxy)phenyl]-1,3,5-triazine,        2-(2-hydroxyphenyl)-4-(4-methoxyphenyl)-6-phenyl-1,3,5-triazine,        2-{2-hydroxy-4-[3-(2-ethylhexyl-1-oxy)-2-hydroxypropyloxy]phenyl}-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine.

3. Metal deactivators, for example, N,N′-diphenyloxalamide,N-salicylal-N′-salicyloyl hydrazine, N,N′-bis(salicyloyl)hydrazine,N,N′-bis(3,5-di-t-butyl-4-hydroxyphenyl-propionyl)hydrazine,3-salicyloylamino-1,2,4-triazole, bis(benzylidene)oxalyl dihydrazide,oxanilide, isophthaloyl dihydrazide, sebacoyl bisphenylhydrazide,N,N′-diacetyladipoyl dihydrazide, N,N′-bis(salicyloyl)oxalyldihydrazide, N,N′-bis(salicyloyl)thiopropionyl dihydrazide.

4. Phosphites, phosphines and phosphonites, for example triphenylphosphite, diphenyl alkyl phosphites, phenyl diallyl phosphites,tris(nonylphenyl) phosphite, trilauryl phosphite, trioctadecylphosphite, trimethylphosphine, tri-n-butylphosphine, triphenylphosphine,distearyl pentaerythritol diphosphite, tris(2,4-di-t-butylphenyl)phosphite, diisodecyl pentaerythritol diphosphite,bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite,bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite,bisisodecyloxypentaerythritol diphosphite,bis(2,4-di-t-butyl-6-methylphenyl)pentaerythritol diphosphite,bis(2,4,6-tri-t-butylphenyl)pentaerythritol diphosphite, tristearylsorbitol triphosphite, tetrakis(2,4-di-t-butylphenyl) 4,4′-biphenylenediphosphonite,6-isooctyloxy-2,4,8,10-tetra-t-butyl-12H-dibenzo[d,g]-1,3,2-dioxaphosphocin,6-fluoro-2,4,8,10-tetra-t-butyl-12-methyl-dibenzo[d,g]-1,3,2-dioxaphosphocin,bis(2,4-di-t-butyl-6-methylphenyl)methyl phosphite,bis(2,4-di-t-butyl-6-methylphenyl)ethyl phosphite,2,2′,2″-nitrilo[triethyl-tris(3,3′,5,5″tetra-t-butyl-1,1′-biphenyl-2,2′-diyl)phosphite],2-ethylhexyl(3,3′,5,5′-tetra-t-butyl-1,1′-biphenyl-2,2′-diyl)phosphite.

Particular preference is given to using the following phosphites:tris(2,4-Di-t-butylphenyl)phosphite (Irgafos® 168, Ciba SpecialtyChemicals), tris(nonylphenyl) phosphite and the phosphites selected fromthe group comprising the structural formulae (a), (b), (c), (d), (e),(f) and (g) given below:

5. Hydroxylamines, for example N,N-dibenzylhydroxylamine,N,N-diethylhydroxylamine, N,N-dioctylhydroxylamine,N,N-dilaurylhydroxylamine, N,N-ditetradecylhydroxylamine,N,N-dihexadecylhydroxylamine, N,N-dioctadecylhydroxylamine,N-hexadecyl-N-octadecylhydroxylamine,N-heptadecyl-N-octadecylhydroxylamine, N,N-dialkylhydroxylamine fromhydrogenated tallow fatty amines.

6. Nitrones, for example N-benzyl α-phenyl nitrone, N-ethyl α-methylnitrone, N-octyl α-heptyl nitrone, N-lauryl α-undecyl nitrone,N-tetradecyl α-tridecyl nitrone, N-hexadecyl α-pentadecyl nitrone,N-octadecyl α-heptadecyl nitrone, N-hexadecyl α-heptadecyl nitrone,N-octadecyl α-pentadecyl nitrone, N-heptadecyl α-heptadecyl nitrone,N-octadecyl α-hexadecyl-nitrone, and nitrones derived fromN,N-dialkylhydroxylamines prepared from hydrogenated tallow fattyamines.

7. Thiosynergists, for example dilauryl or distearyl thiodipropionate.

8. Peroxide scavengers, for example esters of l-thiodipropionic acid,for example the lauryl, stearyl, myristyl or tridecyl esters,mercaptobenzimidazole, the zinc salt of 2-mercaptobenzimidazole, zincdibutyldithiocarbamate, dioctadecyl disulphide, pentaerythritoltetrakis-(lβ-dodecylmercapto)propionate.

9. Polyamide stabilisers, for example copper salts in combination withiodides and/or phosphorus compounds and salts of divalent manganese.

10. Basic co-stabilisers, for example melamine, polyvinylpyrrolidone,dicyandiamide, triallyl cyanurate, urea derivatives, hydrazinederivatives, amines, polyamides, polyurethanes, alkali metal salts andalkaline earth metal salts of higher fatty acids, for example calciumstearate, zinc stearate, magnesium behenate, magnesium stearate, sodiumricinoleate, potassium palmitate, antimony pyrocatecholate or zincpyrocatecholate.

11. Nucleating agents, for example inorganic substances, such as talc,metal oxides, such as titanium dioxide or magnesium oxide, phosphates,carbonates or sulphates of, preferably, alkaline earth metals; organiccompounds, such as mono- or polycarboxylic acids and their salts, suchas 4-t-butylbenzoic acid, adipic acid, diphenyl acetic acid, sodiumsuccinate or sodium benzoate; and polymeric compounds, for example ioniccopolymers (ionomers).

12. Benzofuranones and indolinones, as described, for example, in U.S.Pat. No. 4,325,863; U.S. Pat. No. 4,338,244; U.S. Pat. No. 5,175,312,U.S. Pat. No. 5,216,052; U.S. Pat. No. 5,252,643; DE-A-4 316 611; DE-A-4316 622; DE-A-4 316 876; EP-A-0 589 839 or EP-A-0 591 102, or3-[4-(2-acetoxyethoxy)phenyl]-5,7-di-t-butylbenzofuran-2-one,5,7-di-t-butyl-3-[4-(2-stearoyloxyethoxy)phenyl]benzofuran-2-one,3,3′-bis[5,7-di-t-butyl-3-(4-[2-hydroxyethoxy]phenyl)benzofuran-2-one],5,7-di-t-butyl-3-(4-ethoxyphenyl)benzofuran-2-one,3-(4-acetoxy-3,5-dimethylphenyl)-5,7-di-t-butylbenzofuran-2-one,3-(3,5-dimethyl-4-pivaloyloxyphenyl)-5,7-di-t-butylbenzofuran-2-one,3-(3,4-dimethylphenyl)-5,7-di-t-butylbenzofuran-2one,3-(2,3-dimethylphenyl)-5,7-di-t-butylbenzofuran-2-one.

13. Other additives, for example plasticisers, lubricants, emulsifiers,pigments, rheological additives, catalysts, levelling assistants,optical brighteners, flame proofing agents, antistatic agents or blowingagents.

A preferred embodiment of the invention relates to an aqueous dispersioncomprising

-   -   a) 1.0-80.0% (By weight) of a compound of the formula (I);    -   b) 0.1-10.0% Polyvinyl alcohol having a degree of polymerisation        of about 500-2 500 and a degree of hydrolysis of about        70.0-99.9%; and, optionally, further additives; and    -   c) Water as the remainder to make 100.0% by weight.

A particularly preferred embodiment relates to an aqueous dispersioncomprising

-   -   a) Octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate;    -   b) Polyvinyl alcohol having a degree of polymerisation of about        500-2 500 and a degree of hydrolysis of about 79.0-94.0%; and,        optionally, further additives; and    -   c) Water as the remainder to make 100.0% by weight.

A highly preferred embodiment relates to an aqueous dispersioncomprising

-   -   a) 10.0-60.0% (By weight)        octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate;    -   b) 0.1-10.0% Polyvinyl alcohol having a degree of polymerisation        of about 500-2 500 and a degree of hydrolysis of about        79.0-94.0%; and, optionally, further additives; and    -   c) Water as the remainder to make 100.0% by weight.

Another highly preferred embodiment relates to an aqueous dispersioncomprising

-   -   a) 40.0-50.0% (By weight)        octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate;    -   b) 1.0-5.0% Polyvinyl alcohol having a degree of polymerisation        of about 500-2 500 and a degree of hydrolysis of about        79.0-94.0%; and, optionally, further additives; and    -   c) Water as the remainder to make 100.0% by weight.

The process for preparing the aqueous dispersion defined above is noveland inventive. Therefore, the present invention also relates to aprocess for preparing the aqueous dispersion defined above which ischaracterised in that a molten phase of the compound (I) is dispersed inan aqueous phase, wherein polyvinyl alcohol having a degree ofpolymerisation of about 500-2500 and a degree of hydrolysis of about70.0-99.9%; and, optionally, further additives are present.

In a preferred embodiment of the process, an emulsion of the o/w-typecomprising the components a) and b) within the aqueous phase isobtained. The emulsion is characterised by long storage stability.Another advantage of the process is seen in the fact that crystallinesolids of phenolic antioxidants are reduced to desirable particle sizeswithout wet-grinding the solid. This reduces the costs for preparingdispersions of phenolic antioxidants.

According to a preferred embodiment of the process a solid compound ofthe formula (I) or mixture with other compounds of the formula (I) isheated, particularly to temperatures between 55° C. and 100° C., to givea melt which is then dispersed in an aqueous dispersion comprising from2.0 to 20.0% (by weight) polyvinyl alcohol having a degree ofpolymerisation of about 500-2 500 and a degree of hydrolysis of about70.0-99.9%; and, optionally, further additives. The amount of a compoundof the formula (I) to be dispersed may vary within wide limits to give aconcentration between about 1.0-80.0% (by weight), preferably10.0-60.0%, and most preferably 40.0-50.0%, of a compound of the formula(I). The dispersion is made homogeneous by conventional mixing methods,such as the ones known for preparing emulsions. Mixing can be effectedby vigorous shaking using a dispersing machine, for example a Vortexmixer, or using dispersing machines of the ®POLYTRON type (KinematicaAG, Littau Switzerland) or dispersing machines produced by IKA (StaufenGermany), a static mixer and conventional stirring machines having apropeller or paddle blade or using a magnetic stirrer or phase mixer.

In order to obtain an especially homogeneous mixture, stirring iscarried out at high speed, for example using Y-beam agitators(®Y-Strahl, ®Ultraturrax) or stirring machines produced by Polytron, forexample Polytron PT 3000 or DH 30/30 or using a high pressurerotor/stator mixer, for example the BUSS-Mischturbine.

Approximately from 0.1 to 90.0% by weight of the constituents (withoutthe water component), based on the total weight of the dispersion,preferably approximately from 1.0 to 60.0% by weight, can be dispersedin the aqueous phase. In the event that no recrystallisation occurs, thedispersion obtainable can be defined as an emulsion. The emulsion isstorage stable under the following conditions, at 0-40° C. for a periodof at least 3 months.

By means of analytical measurements from microscopic, laser lightscattering or electron micrographs, the size and homogeneity of theparticles present in the aqueous dispersion, e.g. droplets or solidparticles, is determined.

An average droplet size (X50) of less than 1.5μ for a population of ≧99%(X99) <6.0μ is typical. In the event that solid particles are present,an average particle size (X50) of less than 2.0μ for a population of≧99% (X99) <15.0μ is observed.

A representative sample, as determined by droplet size analysis by laserlight scattering (Sympatec Helos), is characterised by a median dropletsize of 1.3μ (X50) and 90%<3.0μ (X90) and a maximum droplet size of<5.0μ (X99).

Subsequent recrystallisation with the conversion to an aqueousdispersion comprising solid particles is carried out, if desired, byinoculating the emulsion with suitable crystal seeds. The crystalspresent in the aqueous dispersion may then, if desired, be converted tosmaller particles sizes by conventional grinding methods, such as wetgrinding with a ball mill. Even though the wet grinding step is carriedout subsequently, a clear advantage is seen in the fact that crystals ofdesirable particle size are obtained from a melt rather than other formsof solids, such as powders or precipitates. This prevents the inclusionof air or other undesirable particles.

A further embodiment of the invention relates to the further processingof the aqueous dispersion defined above. The dispersion is particularlysuitable for stabilising organic material, especially polymers,specifically styrene (co) polymers, such as polystyrene, ABS(acrylonitrile-butadiene-styrene), IPS (impact polystyrene, graftcopolymer of styrene on polybutadiene), MBS(methacrylonitrile-butadiene-styrene) and SBS(styrene-butadiene-styrene). In this context, they act in particular asantioxidants.

Another embodiment the invention relates to polymer compositionscomprising

-   -   a′) A compound of the formula (I), wherein R₁, R₂, R₃, x and y        are as defined above and, optionally further additives;    -   b′) Polyvinyl alcohol having a degree of polymerisation of        500-2500 and a degree of hydrolysis of 70.0-99.9%; and    -   c′) The polymer material to be stabilised against oxidative,        thermal or light-induced degradation. Another preferred        embodiment the invention relates to polymer compositions        comprising    -   a′) 1.0-40.0% (By weight) of a compound of the formula (I),        wherein R₁, R₂, R₃, x and y are as defined above and, optionally        further additives;    -   b′) 0.1-5.0% Polyvinyl alcohol having a degree of polymerisation        of 500-2500 and a degree of hydrolysis of 70.0-99.9%; and    -   c′) 10.0-95.0% Polymer material to be stabilised against        oxidative, thermal or light-induced degradation.

The incorporation into the polymer materials can be carried out, forexample, by mixing in the composition and, if desired, further additivesin accordance with known methods. The incorporation into the polymericmaterial may take place prior to or during the shaping operation or byapplying the composition to the polymer, with or without subsequentevaporation of the solvent. In the case of elastomers, these can also bestabilised as lattices. The invention therefore relates in particular tocompositions, wherein the dispersion defined above is incorporated intoand/or chemically linked with an elastomer/polymer.

The aqueous dispersion can also be added in the form of a master batch,which contains the individual components defined above in aconcentration, for example, of from 2.5 to 25.0% by weight, to thepolymer material which is to be stabilised.

The dispersion defined above can expediently be incorporated intopolymers by the following methods:

-   -   As emulsion or dispersion (e.g. to lattices or emulsion        polymers);    -   As a dry mix during the mixing in of additional components or        polymer mixtures;    -   By direct addition to the processing apparatus (e.g. extruder,        internal mixer, etc.);    -   As a solution or melt.

Therefore, the present invention also relates to the process for thepreparation of the polymer composition, which comprises incorporatingwithin the polymer material to be stabilised against oxidative, thermalor light-induced degradation the aqueous dispersion defined above.

The polymer compositions can be employed in various forms and processedto give various products, for example as or to films, fibres, tapes,moulding compounds or profiles, or as binders for coating materials,adhesives or putties.

Examples of polymer materials to be stabilised are:

-   1. Polymers of monoolefins and diolefins, for example polypropylene,    polyisobutylene, polybut-1-ene, poly4-methylpent-1-ene, polyisoprene    or polybutadiene, as well as polymers of cycloolefins, for example    of cyclopentene, norbornene or dicyclopentadiene; furthermore    polyethylene (which optionally can be crosslinked), for example high    density polyethylene (HDPE), low density polyethylene (LDPE), linear    low density polyethylene (LLDPE), branched low density polyethylene    (BLDPE).-    Polyolefins, i.e. polymers of monoolefins exemplified in the    preceding paragraph, in particular polyethylene and polypropylene,    can be prepared by different, and especially by the following,    methods:    -   a) Radical polymerisation (normally under high pressure and at        elevated temperature)    -   b) Catalytic polymerisation using a catalyst that normally        contains one or more metals of group IVb, Vb, VIb or VIII of the        Periodic Table. These metals usually have one or more ligands,        such as oxides, halides, alcoholates, esters, ethers, amines,        alkyls, alkenyls and/or aryls that may be either π- or        σ-coordinated. These metal complexes may be in the free form or        fixed on substrates, for example on activated magnesium        chloride, titanium(III) chloride, alumina or silicon oxide.        These catalysts may be soluble or insoluble in the        polymerisation medium. The catalysts can be active as such in        the polymerisation or further activators may be used, for        example metal alkyls, metal hydrides, metal alkyl halides, metal        alkyl oxides or metal alkyloxanes, the metals being elements of        groups Ia, IIa and/or IIIa of the Periodic Table. The activators        may be modified, for example, with further ester, ether, amine        or silyl ether groups. These catalyst systems are usually termed        Phillips, Standard Oil Indiana, Ziegler (Natta), TNZ (DuPont),        metallocene or single site catalysts (SSC).-   2. Mixtures of the polymers mentioned under 1), for example mixtures    of polypropylene with polyisobutylene, polypropylene with    polyethylene (for example PP/HDPE, PP/LDPE) and mixtures of    different types of polyethylene (for example LDPE/HDPE).-   3. Copolymers of monoolefins and diolefins with each other or with    other vinyl monomers, for example ethylene-propylene copolymers,    linear low density polyethylene (LLDPE) and mixtures thereof with    low density polyethylene (LDPE), propylene-but-1-ene copolymers,    propylene-isobutylene copolymers, ethylene-but-1-ene copolymers,    ethylene-hexene copolymers, ethylene-methylpentene copolymers,    ethylene-heptene copolymers, ethylene-octene copolymers,    propylene-butadiene copolymers, isobutylene-isoprene copolymers,    ethylene-alkyl acrylate copolymers, ethylene-alkyl methacrylate    copolymers, ethylene-vinyl acetate copolymers and their copolymers    with carbon monoxide or ethylene-acrylic acid copolymers and their    salts (ionomers) as well as terpolymers of ethylene with propylene    and a diene such as hexadiene, dicyclopentadiene or    ethylidene-norbornene; and mixtures of such copolymers with one    another and with polymers mentioned under 1), for example    polypropylene-ethylene-propylene copolymers, LDPE-ethylene-vinyl    acetate copolymers, LDPE-ethylene-acrylic acid copolymers,    LLDPE-ethylene-vinyl acetate copolymers, LLDPE-ethylene-acrylic acid    copolymers and alternating or random polyalkylene-carbon monoxide    copolymers and mixtures thereof with other polymers, for example    polyamides.-   4. Hydrocarbon resins (for example C₅-C₉) including hydrogenated    modifications thereof (e.g. tackifier resins) and mixtures of    polyalkylenes and starch.-   5. Polystyrene, poly(p-methylstyrene), poly(alpha-methylstyrene).-   6. Copolymers of styrene or alpha-methylstyrene with dienes or    acrylic derivatives, for example styrene-butadiene,    styrene-acrylonitrile, styrene-alkyl methacrylate,    styrene-butadiene-alkyl acrylate, styrene-butadiene-alkyl    methacrylate, styrene-maleic anhydride, styrene-acrylonitrile-methyl    acrylate; mixtures of high impact strength of styrene co-polymers    and another polymer, for example a polyacrylate, a diene polymer or    an ethylene-propylene-diene terpolymer; and block copolymers of    styrene such as styrene-butadiene-styrene (SBS),    styrene-isoprene-styrene, styrene-ethylene-butylene-styrene or    styrene-ethylene-propylene-styrene.-   7. Graft copolymers of styrene or alpha-methylstyrene, for example    styrene on polybutadiene, styrene on polybutadiene-styrene or    polybutadiene-acrylonitrile copolymers, styrene and acrylonitrile    (or methacrylonitrile) on polybutadiene; styrene, acrylonitrile and    methyl methacrylate on polybutadiene; styrene and maleic anhydride    on polybutadiene; styrene, acrylonitrile and maleic anhydride or    maleimide on polybutadiene; styrene and maleimide on polybutadiene,    styrene and alkyl acrylates or alkyl methacrylates on polybutadiene,    styrene and acrylonitrile on ethylene-propylene-diene terpolymers,    styrene and acrylonitrile on polyalkyl acrylates or polyalkyl    methacrylates, styrene and acrylonitrile on acrylate-butadiene    copolymers, as well as mixtures thereof with the copolymers    mentioned under 6), for example the copolymer mixtures known as ABS,    MBS, ASA or AES polymers.-   8. Halogen-containing polymers such as polychloroprene, chlorinated    rubber, chlorinated or sulphochlorinated polyethylene, copolymers of    ethylene and chlorinated ethylene, epichlorohydrine homo- and    copolymers, especially polymers of halogen-containing vinyl    compounds, for example polyvinyl chloride, polyvinylidene chloride,    polyvinyl fluoride, polyvinylidene fluoride; as well as copolymers    thereof such as vinyl chloride-vinylidene chloride, vinyl    chloride-vinyl acetate or vinylidene chloride-vinyl acetate.-   9. Polymers derived from α,β-unsaturated acids and derivatives    thereof such as polyacrylates and polymethacrylates, polymethyl    methacrylates, polyacrylamides and polyacrylonitriles,    impact-modified with butyl acrylate.-   10. Copolymers of the monomers mentioned under 9) with each other or    with other unsaturated monomers, for example acrylonitrile-butadiene    copolymers, acrylonitrile-alkyl acrylate copolymers,    acrylonitrile-alkoxyalkyl acrylate copolymers, acrylonitrile-vinyl    halide copolymers or acrylonitrile-alkyl methacrylate-butadiene    terpolymers.-   11. Polymers derived from unsaturated alcohols and amines or the    acyl derivatives or acetals thereof, such as polyvinyl alcohol,    polyvinyl acetate, polyvinyl stearate, polyvinyl benzoate, polyvinyl    maleate, polyvinyl butyral, polyallyl phthalate or    polyallylmelamine; as well as their copolymers with olefins    mentioned in paragraph 1.-   12. Homopolymers and copolymers of cyclic ethers such as    polyalkylene glycols, polyethylene oxide, polypropylene oxide or    copolymers thereof with bisglycidyl ethers.-   13. Polyacetals such as polyoxymethylene and those polyoxymethylenes    that contain comonomers, for example ethylene oxide; polyacetals    modified with thermoplastic polyurethanes, acrylates or MBS.-   14. Polyphenylene oxides and sulphides, and mixtures thereof with    styrene polymers or polyamides.-   15. Polyurethanes derived from hydroxyl-terminated polyethers,    polyesters and polybutadienes on the one hand and aliphatic or    aromatic polyisocyanates on the other, as well as precursors    thereof.-   16. Polyamides and co polyamides derived from diamines and    dicarboxylic acids and/or from aminocarboxylic acids or the    corresponding lactams, such as polyamide 4, 6, 6/6, 6/10, 6/9, 6/12,    4/6, 12/12, 11 and 12, aromatic polyamides starting from m-xylene,    diamine and adipic acid; polyamides prepared from    hexamethylenediamine and isophthalic and/or terephthalic acid and    with or without an elastomer as modifier, for example    poly-2,4,4-trimethylhexamethylene terephthalamide or    poly-m-phenylene isophthalamide. Block copolymers of the    aforementioned polyamides with polyolefins, olefin copolymers,    ionomers or chemically bonded or grafted elastomers; or with    polyethers, e.g. with polyethylene glycol, polypropylene glycol or    polytetramethylene glycol. As well as polyamides or copolyamides    modified with EPDM or ABS; and polyamides condensed during    processing (RIM polyamide systems).-   17. Polyureas, polyimides, polyamide-imides and polybenzimidazoles.-   18. Polyesters derived from dicarboxylic acids and dialcohols and/or    from hydroxycarboxylic acids or the corresponding lactones, such as    polyethylene terephthalate, polybutylene terephthalate,    poly-1,4-dimethylolcyclohexane terephthalate, polyhydroxybenzoates,    as well as block polyether esters derived from hydroxyl-terminated    polyethers; and also polyesters modified with polycarbonates or MBS.-   19. Polycarbonates and polyester carbonates.-   20. Polysulphones, polyether sulphones and polyether ketones.-   21. Crosslinked polymers derived from aldehydes on the one hand and    phenols, urea or melamine on the other hand, such as    phenol/formaldehyde resins, urea/formaldehyde resins and    melamine/formaldehyde resins.-   22. Drying and non-drying alkyd resins.-   23. Unsaturated polyester resins derived from co polyesters of    saturated and unsaturated dicarboxylic acids with polyhydric    alcohols and vinyl compounds as cross-linking agents, and also    halogen-containing modifications thereof of low flammability.-   24. Crosslinkable acrylic resins derived from substituted acrylates,    for example from epoxy acrylates, urethane acrylates or polyester    acrylates.-   25. Alkyd resins, polyester resins and acrylate resins crosslinked    with melamine resins, urea resins, polyisocyanates or epoxy resins.-   26. Crosslinked epoxy resins derived from polyepoxides, for example    from bisglycidyl ethers, or cycloaliphatic diepoxides.-   27. Natural polymers such as cellulose, natural rubber, gelatin and    derivatives thereof which have been chemically modified in a    polymer-homologous manner, for example cellulose acetates, cellulose    propionates and cellulose butyrates, or the cellulose ethers such as    methylcellulose; and also rosins and derivatives.-   28. Blends (polyblends) of the aforementioned polymers, for example    PP/EPDM, polyamide/EPDM or ABS, PVC/EVA, PVC/ABS, PVC/MBS, PC/ABS,    PBTP/ABS, PC/ASA, PC/PBT, PVC/CPE, PVC/acrylates, POM/thermoplastic    PUR, PC/thermoplastic PUR, POM/acrylate, POM/MBS, PPO/HIPS, PPO/PA    6.6 and copolymers, PA/HDPE, PA/PP or PA/PPO.-   29. Aqueous emulsions of natural or synthetic rubbers, for example    natural rubber latex or lattices of carboxylated styrene-butadiene    copolymers.-   30. Natural and synthetic organic substances which are pure    monomeric compounds or mixtures thereof, for example mineral oils,    animal or vegetable fats, oils and waxes, or oils, waxes and fats    based on synthetic esters (e.g. phthalates, adipates, phosphates or    trimellitates), and also blends of synthetic esters with mineral    oils in any desired proportions by weight, as are employed, for    example, as spin finishes, and also the aqueous emulsions thereof.

The invention also relates to compositions comprising the componentsa′), b′) and c′) and additives customarily present in polymercompositions.

Such additives can be added in small amounts, e.g. UV absorbers or lightstabilisers, for example from the series of hydroxyphenylbenzotriazoles,hydroxyphenylbenzophenones, oxalamides and hydroxyphenyl-s-triazines.Especially suitable are light stabilisers from the group of so-calledsterically hindered amines (HALS), e.g. the2-(2-hydroxyphenyl)-1,3,5-triazine or 2-hydroxyphenyl-2H-benzotriazoletypes. Examples of light stabilisers of the2-(2-hydroxyphenyl)-1,3,5-triazine type are known from the patentliterature, e.g. U.S. Pat. No. 4,619,956, EP-A-434 608, U.S. Pat. No.5,198,498, U.S. Pat. No. 5,322,868, U.S. Pat. No. 5,369,140, U.S. Pat.No. 5,298,067, WO-94/18278, EP-A-704 437, GB-A-2 297 091 or WO-96/28431.

The polymer compositions defined above may comprise additionaladditives, too, for example thickeners, fillers, e.g. calcium carbonate,silicates, glass or glass fibre material, talcum, kaolin, mica, bariumsulphate, metal oxides and hydroxides, carbon black, graphite, powderedwood and powdered or fibrous material of other natural products,synthetic fibres, plasticisers, lubricants, emulsifiers, pigments, flowauxiliaries, catalysts, optical brighteners, flame-retardants,antistatics and blowing agents.

The compositions according to the present invention can be used for avery wide variety of technical applications, for example as adhesives,detergent adjuvants, detergents, dispersants, emulsifiers, surfactants,antifoams, tackifiers, corrosion inhibitors, viscosity improvers,lubricants, flow improvers, thickeners, cross linking agents, asadditives for water treatment, electronic materials, paints andlacquers, coatings, inks, photo developers, super absorbents, cosmetics,preservatives, or as biocides or modifiers and adjuvants for asphalt,textiles, ceramics and wood.

The following Examples illustrate the invention (s: second(s); min:minutes; h: hour(s); temperatures in degrees Celsius (° C.); rpm:rotations per minute; l: liter(s); percentages in weight percent basedon the total weight of the composition):

EXAMPLE 1 Preparation of an Aqueous, Non-ionic Emulsion of 50 Weight %Octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate

350 g Octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate(=IRGANOX 1076) powder are melted at 55° C. in a 1 l glass reactionvessel. 350 g of an aqueous non-ionic surfactant solution is prepared ina 1,5 l sulphuration flask by adding 28 g MOWIOL 8-88 (degree ofhydrolysis: 87-89%) to 322 g deionised cold water under stirring. Thesuspension is then heated up to 80-85° C. for 1 hour to ensure acomplete dissolution. The clear colourless solution is then cooled to25° C. The molten mass of low viscosity is dosed to the cooledsurfactant solution at 53-55° C. during 30 min and dispersed vigorouslyfor 35-40 min using a Y-beam stirrer (10 000 to 15 000 rpm, 45 mmdiameter), keeping the dispersion at 25-30° C. with a water bath.

A storage stable, finely dispersed o/w emulsion of 50% IRGANOX 1076 isobtained which has the following properties:

-   -   pH: 6.2-6.5    -   Droplet size distribution (laser light diffraction analysis with        Sympatec analyser Helos): median value (X50)=1.2-1.4μ and        percentage of droplet >5.0μ lower than 1% (X99 <5μ)    -   Dynamic viscosity (at 25° C., depends on shear velocity        (viscoelastic)): 875 mPa.s at 139/s and 1270 mPa.s at 58/s        (Haake viscosimeter type VT50, rotative element: MV DIN)    -   Storage stability at 40° C.: no phase separation no        crystallisation within 3 months

No crystallisation is observed after inoculation of seed crystals at astorage temperature up to 40° C.

EXAMPLE 2

108 g IRGANOX 1076 are melted at 60° C. in a 1 l glass reaction vessel.432 g Ethylene-bis(oxyethylene)-bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)-propionate](=IRGANOX 245) are added in portions to the molten mass and dissolvedtherein at 80-90° C. 660 g of an aqueous non-ionic surfactant dispersionis prepared in a 1.5 l sulphuration flask by adding and dissolving 60 gMOWIOL 8-88 to 600 g deionised water like in Example 1. The solution iskept at 85° C. in a water bath. The molten mixture of moderate viscosity(160 mPa.s) is added at 90° C. for 15-20 min to the surfactant solutionand then emulgated at 85-87° C. under medium agitation (propellerstirrer, 500-700 rpm) to obtain a droplet size from up to 30μ. At theend of the addition the emulsion is further emulgated for further 30 minby stirring with a Y-beam stirrer at a speed varying from 5 000 up to 15000 rpm. The emulsion is then cooled down for 15 min under normalstirring (propeller stirrer, 250 rpm) to room temperature.

A storage stable, finely dispersed emulsion is obtained, which has thefollowing properties:

-   -   Microscopic and laser diffraction analysis reveal a median        droplet size of 1.1μ and a maximum droplet size (X99) of 3.1μ    -   The flow properties of the emulsion are Newtonian. Dynamic        viscosity: 585-600 mPa.s at 25° C. (Viscosimeter type HAAKE        VT50, rotative element MV DIN)    -   The emulsion is storage stable at least 1 week at room        temperature. Suitable by-products (<0.2% by weight) can be added        to increase the shelf time if desired    -   Partial recrystallisation of IRGANOX 245 can be observed during        storage at T>25° C. especially at the interface liquid/air.

1. An aqueous dispersion comprising a) a compound of the formula:

 wherein  one of R₁ and R₂ independently of one another representshydrogen or C₁-C₄alkyl and the other one represents C₃-C₄alkyl;  xrepresents zero (direct bond) or a numeral from one to three; and  R₃represents C₈-C₂₂alkyl or a group of the partial formulae

 wherein  one of R₁′ and R₂′ independently of one another representshydrogen or C₁-C₄alkyl and the other one represents C₃-C₄alkyl;  xrepresents zero (direct bond) or a numeral from one to three; and  yrepresents a numeral from two to six; b) polyvinyl alcohol having adegree of polymerisation of about 500-2500 and a degree of hydrolysis ofabout 70.0-99.9%; and, optionally, further additives; and c) water. 2.An aqueous dispersion according to claim 1 comprising a) 1.0-80.0% (byweight) of a compound of the formula (I); b) 0.1-10.0% polyvinyl alcoholhaving a degree of polymerisation of about 500-2500 and a degree ofhydrolysis of about 70.0-99.9%; and, optionally, further additives; andc) water as the remainder to make 100.0% by weight.
 3. An aqueousdispersion according to claim 1 comprising a)octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate; b) polyvinylalcohol having a degree of polymerisation of about 500-2500 and a degreeof hydrolysis of about 79.0-94.0%; and, optionally, further additives;and c) water as the remainder to make 100.0% by weight.
 4. An aqueousdispersion according to claim 3 comprising a) 10.0-60.0% (by weight)octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate; b) 0.1-10.0%polyvinyl alcohol having a degree of polymerisation of about 500-2 500and a degree of hydrolysis of about 79.0-94.0%; and, optionally, furtheradditives; and c) water as the remainder to make 100.0% by weight.
 5. Anaqueous dispersion according to claim 3 comprising a) 40.0-50.0% (byweight) octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; b)1.0-5.0% polyvinyl alcohol having a degree of polymerisation of about500-2 500 and a degree of hydrolysis of about 79.0-94.0%; and,optionally, further additives; and c) water as the remainder to make100.0% by weight.
 6. A process for preparing an aqueous dispersionaccording to claim 1, which process comprises dispersing a molten phaseof the compound (I) in an aqueous phase, wherein polyvinyl alcoholhaving a degree of polymerisation of about 500-2500 and a degree ofhydrolysis of about 70.0-99.9%; and, optionally, further additives arepresent.
 7. A composition comprising a′) a compound of the formula (I)according to claim 1 and, optionally further additives; b′) polyvinylalcohol having a degree of polymerisation of 500-2500 and a degree ofhydrolysis of 70.0-99.9%; and c′) a polymer material to be stabilisedagainst oxidative, thermal or light-induced degradation.
 8. A processfor the preparation of a polymer composition, which process comprisesincorporating within a polymer material to be stabilised againstoxidative, thermal or light-induced degradation an aqueous dispersionaccording to claim 1.